Party-line telephone-exchange system



April 29, 1924. 1,492,219

R. L. QUASS PARTY LINE TELEPHONE EXCHANGE SYSTEM Filed Dec. 22 1920- Mme/War." fia/ph L. Quaas Patented Apr. 2, i924.

"PATENT;"OFFICE.

RALPH L. QUASS, or HAWTHORNE, NEW JERSEY, ASSIGNOR.TO wnsrnan anaemic COMPANY, moonronarnn, or new YORK, n, Y., a conronarron or NEW Yonx.

PARTY-LINETELEPHONE-EXCHANGE SYSTEM. 3

Application filed December 22, 1920. Serial No. 432,471.

To all whom it may concern: 1

- Be it known that I, RALPH L. QUAss, a citizen of the United States, residing at Hawthorne, in the county of Passaic, State a of New Jersey, have invented certain new and useful Improvements in Party-Line Telephone-Exchange Systems, of which-the following is a full, clear, concise,- andexaot description. I I 30 This invention relates-to machine switching telephone exchanges employing'party line working, and more particularly to that type of system wherein the subscribers on the party lines signal other parties on the W same line by means ofa special codewhich causes ringing relays at the exchange to selectively ring back on the line and ring the bells at both the calling and called stations. In this type of system, the calling party m hangs up his receiver after having dialed the digits of the code, such replacement of the receiver causing the starting of the ringing operation.

Such a system is shown for example in 25 Patent No. 1,158,221 of October 26, 1915, to

H. Hovland.

It is the object of this invention to provide a system which will accomplish the same results with less equipment than heretofore ac necessary.

In the patent referred to, a given level of a selector is used for these revertive calls. Each of the trunks from this level terminates in a so-called frequency selector. Each of as these frequency selectors is provided with ringing relays and associated apparatus for picking out the two kinds of current for selectively ringing the bells of the calling and called lines alternately. I M In the arrangement of this invention instead of providing a frequency selector and associated apparatus for each trunk in the level a smaller number is provided and the circuit is so arranged that the selector will as not seize a trunk unless the test indicates that not only the trunk is idle but that an idle frequency selector adapted to servethe same is also idle. Inasmuch as the period during which a frequency selector is used is FM) only a small part of the period during which a trunk is used in a given connection, it is evident that the number of frequency selectors may be smaller than the number of trunks.

Referring to the drawing in which Fig. 1 illustrates the preferred embodiment of my invention, only the brushes and cooperating terminals of the lineswitch LS and first selector FSareshown, since these switches may be the same as those shown in the Hovland patent referred to. It will be understood that both the trunks shown are located in the same level, which level is allotted to revertive signalling. As stated, the party line subscribers in making revertive calls use a special numbering system different from that in making non-revertive calls. Fig. 2 is'a chart showing the combinations of current sent out in each position of the frequency selector switch.

The invention will be more readily understood from 'adetailed descriptionof the op.- eration of the system. vThe removal of the receiver at substation llcauses the line switch to operateto extend the-party line to the first selector FS. This first selector is then set by means of the sender S to the level allotted to revertive calls. It then automatically hunts over the trunks in this level, and upon reaching an idle trunk seizes the same. The seizure of this trunk which we shall presume to be the upper trunk shown in the drawing, operates the stepping relay B, which in operating energizes slow relay C. Relay C in attracting its outer left armature grounds test multiple 100 of the seized trunk to cause the same to test busy and at its inner armature operates relay D over a circuit including the right-hand armature and back contact of relay E, outer left armature of relay D of the lower trunk to ground at the outer left armatureand front contact of slowvrelay C. Relay D at its outer left armature applies ground to the test multiple 101 of the other trunk having ,a'ccessto this frequency selector. The receipt of the impulses correspondingto the seconddigit of the code, causes the relay to transmit impulses from its armature and back contact over the inner right armature and front contact of relay D, slow'relay F, inner left armature and back contact of relay M, motor magnet M of the frequency switch, resistance 102 tobattery. The arms T, R, PU, L and Rel are thus advanced over their terminals. 'Upon the beginnin of the impulses, the relay F closes'a circuit to operate relay J, this circuit including the armature and back contact of relay 108. Relay J in attracting its outer right armature opens the restoring circuit of the motor magnet, and in attracting its inner right armature closes the starting circuit which causes the ringing machine 103 and interrupter 10 1 to operate. the slow relay F releases, removing the shortcircuit to ground at the armature of relay 108 from about the winding of relay K. Relay Know operates'in series with relay J free pole of battery, relays J and K, inner left armature and front contact of relay J, conductor 1'05, inner left armature and front contact of relay D, ground at the armature and back contact of relay 108.

The calling subscriber now hangs up his receiver, deenergizing relay B, but before the slow relay C can release, a substitute circuit therefor is closed at the right armature and front contact of relay A which energizes upon the release of relay'B over the following circuit: free pole of battery, re lay A, outer right armature and front contact of relay D, outer right armature and front contact of relay M, outer left armature and'front contact of relay J, conductor 106, inner right armature of relay D to ground at the back contact of relay B. Assume that the subscriber at substation 1 has called subscriber at substation 4. In order to ringthe bell at these stations, positive current would have to be applied over the ring side, and negative current over the tip side of the line. rteferring to the wiring of .the frequency selector, it will be seen that in order to transmit this combination of currents six impulses would have to be sent to setthe frequency switch in its sixth position. This is evident from an inspection of the diagram shown in the lower left corner of the drawing. When the relay K operated, 1t energized relay M. This relay in attracting its outer left armature connects interrupting machine lO fto the pull up arm 107, wh ch arm is now on its sixth contact. In pos tion 6, the arm L closes a circuit to energize relay- H, this circuit including the inner-left armature andfront contact of relay M, andthe'motor magnet 102 which is marglnal does not operate in this circuit; Due to the operation of relay- H' and-arm- PU beingin its sixth position, the relays G and operated; Each time the interrupting mach ne 104C reaches an insulated segment, thesetwo relays are released; The simultaneous energization ofthese relays, G and P, causespositive current from generator 103 to flow over the ring side of the line to operate the bellxatsubstation 1 only, and each time these relays are released, negative current is transmitted over the tip side of theline to operate the: ringer at substation 4. only. The ringing system-employed: is

Upon the cessation of the impulses the same as shown in Patent No. 7 68,272, to T. C. Drake, issued August 23, 1904:, known as superimposed ringing. The relays G and P will continue to operate to ring the bells at the calling and called substations 1 and 4t alternately, until the called. subscriber at substation at removes his receiver, causing the operation of the ringing cut-off relay 108. This relay in attracting its armature releases relays. J and K. Relay K in turn releases relay M. Relay J releasing its outer left armature, releases relay A which again bridges relay B across the calling line. This relay in attracting its armature'closes the substitute circuit for the slow relay C to prevent premature release. The release of relay A cuts. off the ringing current. The subscribers may now converse, current being supplied to: both transmitters over the windingsof the relay B.

Relay K is slow to. release and consequently holds relay M operated a short time after relay J operates due to relay 108 operating upon response of the called party. Consequently, the following circuit is closed for relay E; free pole of battery relay E, its left contact, conductor 110, right armature and front contact of relay M, outer left armature and back contact of relay J to ground at the armature and baclrcontact of relay B. Relay E in attracting its armature locks itself up to ground at the outer left armature and, front contact of relay 0, and in attracting its right armature opens the circuit which has been holding relay D energized. Relay D in retracting its outer left armature closes a break in the circuit of relay-D which belongs to the lower trunk, restoring the control of the frequency selector to the lower trunk. The function of the relays D and D which are respectively individual to the upper and lower trunks, is to prevent interference with the frequency selector by the one trunk while it is being used by the other.

Upon the termination of the conversation, the subscribers replace their receivers which causes the release of relay B, which opens the circuit of relay 0. This relay in releasing removes ground from the multiple 100 and the sleevewire leading back to the first selector and line switch, causing the release of the same, as described in the said Hovland patent. The retraction of the outer left armature of relay D removes ground from the multiple 101 of the lower trunk to render the same accessible to other first selectors.

The first six terminals of the frequency selector give the required combination of current to enable-any substation to signal any other and itself. The last four terminals are used to ring back on the line for bell adjustment, that is to say, when seven impulses are sent only the bell of the; calling station will be operated upon the replacement of its receiver, etc, The release of the outer right armatureof the relay J closes a self-interrupting circuit from motor magnet MM. This circuit includes the arm Reel of the frequency selector thus causing the frequency selector to step around to its normal position.

It will be seen from the foregoing that by virtue of the present arrangement a calling subscriber merely has to remove his receiver and dial a certain code which will cause one of a number of frequency selectors, less in number than the number of trunks in the level, to select the two desired ringing generators and then upon replacing the receiver upon the hook his bell and the bell of the desired station is rung, the response of the called party causing the ringing to cease, thus indicating to him that the called subscriber has answered. The frequency selector is only removed from access to the other trunk while it is actually ringing the stations, and immediately upon the response of the called party reverts to the use of the other trunk. While a frequency selector for each pair of trunks is shown, that is, five for a level of ten trunks, it will be understood that the invention is not to be so limited. Fewer or more frequency selectors could be provided as the traffic requires.

What is claimed is:

1. In a telephone system, a party line having substation ringers connected thereto, a calling terminal for said line, trunks at the exchange, ring back apparatus at the exchange common to said trunks, means for extending a connection from said line to said ring back apparatus over said calling terminal and one of said trunks and for associating said ring back apparatus with the seized trunk, means for operating said apparatus to project ringing current back over the said calling terminal to the calling line to enable one party to selectively signal another party on the same line, and means operated by the response of one of the parties for causing said ring back apparatus to revert to common use.

2. In a telephone system, a party line having substation ringers connected thereto, a calling terminal for said line, trunks at the exchange, ring back apparatus at the exchange common to said trunks, means for extending a connection from said line to said ring back apparatus over said calling terminal and one of said trunks and for associating said ring back apparatus with the seized trunk, means operated by the taking of the ring back apparatus for use for causing another trunk having access to said ring back apparatus to test busy, and means for operating said apparatus to project ringing current back over the said calling terminal to the calling lineto enable one party to selectively signal another 7 party on the same line.

3. In a telephone system, a party line having substation ringers connected thereto, a calling terminal for said line, trunks at the exchange, ring back apparatus at the exchange common tot said trunks, means for extending a connection from said line to said ring back apparatus over said calling terminal and one of said trunks and for associating said ring back apparatus with the seized trunk, means operated by the re sponse of the called party for causing said ring back apparatus to revert to common use, and means for operating said apparatus to project ringing current back over the said calling terminal to thecalling line to enable one party to selectively signal another party on the same line.

t. In a telephone system, a party line having substation ringers connected thereto, a calling terminal for said line, trunks at the exchange, ring back apparatus at the exchange common to said trunks, means for extending a connection from said line to said ring back apparatu s'over said calling terminal and one of said trunks and for associating said ring back apparatus with the seized trunk, means controlled by the calling party for causing said ring back apparatus to select currents of different frequency to selectively ring both the calling and called stations, means operated by the replacement of the receiver by the calling party for causing the application of the ringing current, and means actuated by the response of the called party for cutting off the ringing current, and for releasing the ring back apparatus for common use.

5. In a telephone system, a party line having substation ringers connected thereto, a calling terminal for said line, trunks at the exchange, ring back apparatus at the exchange common to said trunks, means for extending a connection from said line to said ring back apparatus over said calling terminal and one of said trunks and for associating said ring back apparatus with seized trunk, means operated by the taking of the ring back apparatus for use for causing another trunk having access to said ring back apparatus to test busy, and means for operating said apparatus to project ringing current back over the said calling terminal to the calling line to enable one party to selectively signal another party on the same line, and means operated by the response of the calling party for causing said ring back apparatus to revert to common use, and for removing the artificial busy condition from the other said trunk.

6. In a telephone system, a party line having substation ringers connected thereto, a calling terminal for said line, trunks at the exchange, ring back apparatus at the exboth the calling and called stations, means 30 change common to said trunks, means for operated by the replacement of the receiver extending a connection from said line to said by the calling party for causing the appliring back apparatus over said calling tercation of the ringing current, and means acminal and one of said trunks and for astuated by the response of the called party I sociating said ring back apparatus with the for cutting off the ringing current, and for 35 seized trunk, means controlled by the calling releasing the ring back apparatus for comparty for causing said ring back apparatus mon use. to select currents of different character to 8. In a telephone system, a party line selectively ring both the calling and called having substation ringers connected thereto, stations, means operated by the replacement a calling terminal for said line, a plurality of the receiver by the calling party for causof trunks, means for automatically extend ing the application of the ringing current, ing a calling line to an idle trunk, ring back and means actuated by the response of the apparatus, automatic means actuated upon called party for cutting off the ringing curthe seizure of said trunk for connecting said rent, and for releasing the ring back apring back apparatus to' the seizedtrunk and paratus for common use. for rendering it unselectable, means for op- 7. In a telephone system, a party line crating said apparatus to project ringing having substation ringers connected thereto, current back over said terminal to the calla calling terminal for said line, trunks at ing line to enable one party to signal anthe exchange, ring back apparatus at the other party on the same line, and means for 50 exchange common to said trunks, means for automatically disconnecting said ring back extending a connection from said line to said apparatus upon the response of the called ring back apparatus over said calling terparty and for again rendering the same minal and one of said trunks, and for asselectable.

sociating said ring back apparatus with the In Witness whereof I hereunto subscribe 66 seized trunk, means controlled by the calling my name this 18th'day of December, A. D.

party for causing said ring back apparatus 1920. to select ringing current to selectively ring RALPH L. QUASS. 

